For a decent quality of soldering work, a home craftsman, and even more so a radio amateur, will need a simple and convenient temperature controller for the soldering tip. For the first time, I saw a device diagram in the Young Technician magazine of the early 80s, and having collected several copies, I still use it.

To assemble the device you will need:
-diode 1N4007 or any other, with a permissible current of 1A and a voltage of 400 - 600V.
- thyristor KU101G.
- electrolytic capacitor 4.7 microfarads with an operating voltage of 50 - 100V.
-resistance 27 - 33 kilo-ohms with a permissible power of 0.25 - 0.5 watts.
- variable resistor 30 or 47 kilo-ohm SP-1, with a linear characteristic.

For simplicity and clarity, I drew the placement and interconnection of parts.

Before assembly, it is necessary to isolate and mold the leads of the parts. We put on insulating tubes 20 mm long on the conclusions of the thyristor, and 5 mm on the leads of the diode and resistor. For clarity, you can use colored PVC insulation, removed from suitable wires, or heat shrink. Trying not to damage the insulation, we bend the conductors, guided by the drawing and photographs.

All parts are mounted on the terminals of a variable resistor, connected to the circuit with four solder points. We put the conductors of the components into the holes on the terminals of the variable resistor, trim everything and solder it. We shorten the conclusions of the radioelements. The positive terminal of the capacitor, the control electrode of the thyristor, the resistance terminal, are connected together and fixed by soldering. The thyristor case is an anode, for safety, we isolate it.

To give the design a finished look, it is convenient to use the case from the power supply with a power plug.

We drill a hole with a diameter of 10 mm on the upper edge of the case. We insert the threaded part of the variable resistor into the hole and fix it with a nut.

To connect the load, I used two connectors with holes for pins with a diameter of 4 mm. On the case we mark the centers of the holes, with a distance between them of 19 mm. In drilled holes with a diameter of 10 mm. insert connectors, fix with nuts. We connect the plug on the case, the output connectors and the assembled circuit, the soldering points can be protected with heat shrink. For a variable resistor, it is necessary to choose a handle made of insulating material of such a shape and size as to cover the axis and nut. We assemble the case, securely fix the regulator knob.

We check the regulator by connecting an incandescent lamp of 20 - 40 watts as a load. Turning the knob, we are convinced of a smooth change in the brightness of the lamp, from half the brightness to full heat.

When working with soft solders (for example, POS-61), soldering iron EPSN 25, 75% of the power is sufficient (the position of the regulator knob is approximately in the middle of the stroke). Important: on all elements of the circuit there is a supply voltage of 220 volts! Electrical safety measures must be followed.

I am sure that every radio amateur has encountered the problem of falling tracks on the getinax and loose tin. The reason for this is an overheated or insufficiently heated soldering iron tip. How to solve this problem? Yes, it’s very simple, or rather a very simple device, the assembly of which will be possible even for a beginner radio amateur. The circuit diagram of the regulator was once published in a magazine Radio:

About the principle of operation: this scheme makes it possible to adjust the power of the soldering iron or lamp from 50 to 100%. In the lower position of the potentiometer, the thyristor VS1 is closed, and the load is powered through VD2, that is, the voltage is reduced by half. When the potentiometer is rotated, the control circuit begins to open the thyristor and a gradual increase in voltage occurs.

You can take a print. There are two resistors P5 on the board - do not be alarmed, there was simply no required value. If desired, the signet can be miniaturized, I have it sweeping out of principle - in transformerless and power circuits I always breed in a big way - it's safer.

The scheme for the year was used very often and did not have a single failure.

Attention! The soldering iron regulator has a transformerless power supply of 220 V. Follow the safety rules and test the circuit only through a light bulb!

A typical problem when working with a soldering iron is burning the tip. This is due to its high heat. During operation, soldering operations require unequal power, so you have to use soldering irons with different power. To protect the device from overheating and the rate of change in power, it is best to use a temperature-controlled soldering iron. This will allow you to change the operating parameters in a matter of seconds and extend the life of the device.

Origin story

A soldering iron is a tool designed to transfer heat to a material in contact with it. Its direct purpose is to create an integral connection by melting solder.

Before the beginning of the 20th century, there were two types of soldering tools: gas and copper. In 1921, German inventor Ernst Sachs invented and registered a patent for a soldering iron, which was heated by electric current. In 1941, Karl Weller patented a transformer-shaped tool that resembles a pistol in shape. Passing current through its tip, it quickly heated up.

Twenty years later, the same inventor suggested using a thermocouple in a soldering iron to control the heating temperature. The design included two metal plates pressed together with different thermal expansion. Since the mid-60s, due to the development of semiconductor technology, soldering tools began to be produced with a pulsed and induction type of work.

Types of soldering irons

The main difference between soldering devices is their maximum power, on which the heating temperature also depends. In addition, electric soldering irons are divided according to the value of the voltage supplying them. They are produced both for an AC voltage of 220 volts, and for its constant value of various sizes. Separation of soldering irons also occurs according to the type and principle of operation.

According to the principle of work there are:

• nichrome;
• ceramic;
• impulse;
• induction;
• hot air;
• infrared;
• gas;
• open type.

In appearance, they are rod and hammer. The former are designed for spot heating, and the latter for heating a certain area.

Principle of operation

Most devices are based on the conversion of electrical energy into thermal energy. For this, a heating element is located in the inside of the device. But some types of device are simply heated on fire or use an ignited directional gas flow.

Nichrome devices use a wire spiral through which current is passed. The spiral is located on the dielectric. When heated, the spiral transfers heat to the copper sting. The heating temperature is regulated by a temperature sensor, which, when a certain heating value is reached, disconnects the spiral from the electric line, and when it cools down, reconnects it to it. The temperature sensor is nothing more than a thermocouple.

Ceramic soldering irons use rods as heaters. Adjustment in them is most often carried out by lowering the voltage applied to the ceramic rods.

Induction equipment works due to the inductor. The sting is covered with a ferromagnet. With the help of a coil, a magnetic field is induced and currents appear in the conductor, leading to heating of the tip. During operation, there comes a moment when the sting loses its magnetic properties, the heating stops, and when it cools down, the properties return and the heating is restored.

The operation of pulsed soldering irons is based on the use of a high-frequency transformer. The secondary winding of the transformer has several turns made of thick wire, the ends of which are the heaters. The frequency converter increases the frequency of the input signal, which is reduced by the transformer. Heating is controlled by power control.

A hot air soldering iron, or, as it is called, a hot air gun, uses hot air during operation, which heats up when passing through a spiral made of nichrome. The temperature in it can be regulated both by reducing the voltage applied to the wire, and by changing the air flow.

One of the types of soldering irons are devices that use infrared radiation. Their work is based on the process of heating by radiation with a wavelength of up to 10 microns. For regulation, a complex control unit is used that changes both the wavelength and its intensity.

Gas burners are conventional burners that use nozzles of different diameters instead of a sting. Temperature control is almost impossible, except for changing the intensity of the gas output using a damper.

Understanding the principle of operation of the soldering iron, you can not only repair it yourself, but also modify its design, for example, make it adjustable.

Devices for adjustment

The price of soldering irons with temperature control is several times higher than the price of ordinary devices. Therefore, in some cases it makes sense to buy a good ordinary soldering iron, and make the regulator yourself. Thus, soldering equipment is controlled by two control methods:

• power;
• temperature.

Temperature control allows you to achieve more accurate readings, but it is easier to implement power control. In this case, the regulator can be made independent and various devices can be connected to it.

Universal Stabilizer

A soldering iron with a thermostat can be made using a factory-made dimmer or designed by analogy on its own. A dimmer is a regulator that changes the power supplied to the soldering iron. In a 220 volt network, a variable current with a sinusoidal shape flows. If this signal is cut off, then an already distorted sinusoid will be supplied to the soldering iron, which means that the power value will also change. To do this, before the load, a device is included in the gap, which passes the current only at the moment the signal reaches a certain value.

Dimmers are distinguished by the principle of operation. They can be:

• analog;
• impulse;
• combined.

The dimmer circuit is implemented using various radio components: thyristors, triacs, specialized circuits. The simplest dimmer model comes with a mechanical knob. The principle of operation of the model is based on the change in resistance in the circuit. In fact, this is the same rheostat. Dimmers on triacs cut off the leading edge of the input voltage. The controllers use a complex electronic voltage reduction circuit in their work.

It is easier to make a dimmer on your own using a thyristor for this. The circuit does not need scarce parts, and it is assembled by a simple hinged installation.

The operation of the device is based on the ability to open the thyristor at times when a signal is applied to its control output. The input current, acting on the capacitor through a chain of resistors, charges it. In this case, the dinistor opens and passes through itself for a short time the current supplied to the control of the thyristor. The capacitor is discharged and the thyristor closes. At the next cycle, everything repeats. By changing the resistance of the circuit, the duration of the charge of the capacitor is regulated, and hence the time of the open state of the thyristor. Thus, the time is set during which the soldering iron is connected to the 220 volt network.

Simple thermostat

Using the TL431 Zener diode as the basis, you can assemble a simple thermostat with your own hands. Such a circuit consists of inexpensive radio components and practically does not need to be tuned.

The zener diode VD2 TL431 is connected according to the comparator circuit with one input. The value of the required voltage is determined by a divider assembled on resistors R1-R3. As R3, a thermistor is used, the property of which is to reduce the resistance when heated. Using R1, the temperature value is set at which the device turns off the soldering iron from power.

When a signal value exceeding 2.5 volts is reached on the zener diode, it breaks through, and power is supplied through it to the switching relay K1. The relay sends a signal to the control output of the triac and the soldering iron turns on. When heated, the resistance of the temperature sensor R3 decreases. The voltage on the TL431 drops below the compared one and the triac power supply circuit breaks.

For a soldering tool with a power of up to 200 W, the triac can be used without a heatsink. RES55A with an operating voltage of 12 volts is suitable as a relay.

Power boost

It happens that there is a need not only to reduce the power of soldering equipment, but vice versa, to increase it. The meaning of the idea is that you can use the voltage that occurs on the network capacitor, the value of which is 310 volts. This is due to the fact that the mains voltage has an amplitude value greater than its effective value by 1.41 times. From this voltage, pulses of rectangular amplitude are formed.

By changing the duty cycle, you can control the effective value of the pulse signal from zero to 1.41 of the effective value of the input voltage. Thus, the heating power of the soldering iron will vary from zero to twice the rated power.

The input part is a standard assembled rectifier. The output unit is made on a field-effect transistor VT1 IRF840 and is able to switch a soldering iron with a power of 65 watts. The operation of the transistor is controlled by a microcircuit with pulse-width modulation DD1. Capacitor C2 is in the corrective chain and sets the generation frequency. The microcircuit is powered by radio components R5, VD4, C3. Diode VD5 is used to protect the transistor.

Soldering Station

A soldering station is, in principle, the same adjustable soldering iron. Its difference from it is in the presence of a convenient indication and additional devices that help facilitate the soldering process. Usually, an electric soldering iron and a hair dryer are connected to such equipment. If you have experience as a radio amateur, you can try to assemble a soldering station circuit with your own hands. It is based on the microcontroller (MK) ATMEGA328.

Such an MK is programmed on a programmer, Adruino or a home-made device is suitable for this. An indicator is connected to the microcontroller, which is used as a liquid crystal display LCD1602. Station control is simple, for this a variable resistance of 10 kOhm is used. Turning the first one sets the temperature of the soldering iron, the second - the hair dryer, and the third one can reduce or increase the air flow of the hair dryer.

A field-effect transistor operating in a key mode, together with a triac, is installed on a radiator through a dielectric gasket. LEDs are used with low current consumption, not more than 20 mA. The soldering iron and hair dryer connected to the station must have a built-in thermocouple, the signal from which is processed by the MK. The recommended soldering iron power is 40 W, and the hair dryer is no more than 600 W.

The power supply will need 24 volts with a current of at least two amperes. For power, you can use a ready-made adapter from a monoblock or laptop. In addition to stabilized voltage, it contains various types of protection. And you can do it yourself analog type. This will require a transformer with a secondary winding rated for 18-20 volts, and a rectifier bridge with a capacitor.

After assembling the circuit, it is adjusted. All operations consist in adjusting the temperature. First of all, the temperature on the soldering iron is set. For example, we set 300 degrees on the indicator. Then, pressing the thermometer to the tip, with the help of an adjustable resistor, the temperature is set corresponding to the actual readings. The temperature of the hair dryer is calibrated in the same way.

All radioelements are conveniently purchased in Chinese online stores. Such a device, excluding a homemade case, will cost about one hundred US dollars with all accessories. Firmware for the device can be downloaded here: http://x-shoker.ru/lay/pajalnaja_stancija.rar.

Of course, it will be difficult for a novice radio amateur to assemble a digital temperature controller with his own hands. Therefore, you can purchase ready-made temperature stabilization modules. They are boards with soldered connectors and radio components. You only need to buy a case or make it yourself.

Thus, using a soldering iron heating stabilizer, it is easy to achieve its versatility. In this case, the temperature change range is achieved in the range from 0 to 140 percent.

At 12 volts / 8 watts, but the price was somewhat unusual, only 80 rubles against 120, as in other outlets. I was going to do something like this myself, but then the case deprived me of such an opportunity. The seller assured that it was serviceable and even checked it by connecting it to the power supply. Came home and started trying it out. The stabilized IPB is just right for its voltage. Everything seems to be fine, tin melts, only a little slower than usual. In the end, I figured out why the price was understated and why it was “slowed down” in work. It turned out that the soldering iron for normal operation does not need 12 volts, but a little more. I remembered the cheese in the mousetrap, although of course this is a slightly different case. For the full operation of the soldering iron, I decided to assemble a simple voltage regulator and power it from a 17 volt power supply.

Regulator circuit

The scheme is simple “obscenely” (because of which it was even subjected to harsh criticism on one of the related sites) and should, no, simply must work.

However, I made a preliminary assembly. Within an hour, everything was fully mounted on an impromptu circuit board. And components and installation. Immediately there was an opportunity for full-fledged work with a soldering iron.

To test the assembled device, for a complete understanding of the result, I involved a voltmeter and an ammeter. Observation of changes in specific values ​​of current and voltage will always help to be objective to the result of your efforts.

Video

Output voltage up to 16 volts, maximum current consumption up to 500 mA. As a result of the manipulations done, I came to the conclusion that the transistor should be put more powerful. For example KT829A. You never know where I’ll think of connecting a ready-made regulator and what to power through it. This regulator does not provide a stabilized voltage at the output, a slight increase is noticed, albeit a very slow one. And since I plan to produce soldering for a short time, this is not an obstacle.

For a week I used a temporary assembly several times, the work arranged. It's time to give the device a more or less "human" look. I picked up the components: the case, for its stability a metal roller, a soldering iron holder and a connecting screw.

Since I also decided to use the roller as an additional radiator, I isolated it from the soldering iron holder with a plastic washer.

After placing the main components, I installed RGB sockets at the input and output (voltage and current are not large), this will avoid installing permanent wires (which are always always confused). And use ready-made, fully equipped. Since the days of VCRs, there have been plenty of them.

The main components are a transistor and two resistors, but there are still enough wires.

Here's what happened. The LED is not accidentally connected to the output of the regulator - with a change in the output voltage, the brightness of its glow changes, and very significantly. I did not equip the regulator with something like a scale - on the body around there were quite a sufficient number of marks from its former purpose. This is how, thanks to the circuit seen on the site's forum, it was possible to solve the issue of powering a low-voltage soldering iron with a non-standard supply voltage. Assembly made Babay from Barnaula.

Discuss the article STAND AND POWER REGULATOR OF LOW-VOLTAGE SOLDERING IRON

In amateur radio practice, it is impossible to do without a soldering iron. He is always at the workplace, must be ready. Most simple and common soldering irons have a fixed power, and therefore, the heating temperature of the tip, which is not always justified. Of course, if you turn it on for a short time to quickly solder something, then you can do without a temperature controller.

What is a soldering iron tip temperature controller for?

The most common soldering iron produced by the industry has a power of 40 watts. This power is quite enough for soldering large, heat-intensive parts, where heating to the melting temperature of the solder is required.

But using a soldering iron of such power, for example, when installing radio components, is extremely inconvenient. The tin constantly rolls off the overheated tip, the soldering point is fragile. In addition, the sting very quickly becomes covered with scale and it has to be cleaned off, and so-called craters form on the working surface of the copper sting, which can be removed with a file. The length of such a sting will decrease very quickly.

Using tip temperature controller the soldering iron is always ready, its temperature will be optimal for a specific job, you will never overheat the radio components. If you need to leave for a short time, then it is enough to reduce the voltage on the soldering iron, and not turn it off from the network, as before. Upon returning to the workplace, it is enough to add voltage with the regulator, and the warm soldering iron will quickly reach the desired temperature.

Temperature controller circuit for a soldering iron

Below is a simple power regulator circuit:

I used this circuit for my regulator 20 years ago, I still use this soldering iron. Of course, some details, such as: transistors, a neon light bulb, can be replaced with modern ones.

Device details:

• transistors; KT 315G, MP 25 can be replaced by KT 361B
• Thyristor; KU 202N
• zener diode; D 814B or with the letter V
• Diode;KD 202Zh
• Fixed resistors: MLT-3k, 2k-2 pcs, 30k, 100 ohm, 470k
• Variable resistor; 100k
• Capacitor; 0.1uF

As you can see device diagram very simple. Even a beginner can repeat it.

We make a simple do-it-yourself soldering iron temperature controller

The presented device is built on the so-called half-wave power controller. That is, with a fully open thyristor VS 1, which is controlled by transistors VT 1 and VT 2, one half-wave of the mains voltage passes through the diode VD 1, and the other half-wave through the thyristor. If you turn the slider of the variable resistor R 2 in the opposite direction, then the thyristor VS 1 will close, and there will be one half-wave on the load that will pass through the diode VD 1:

Therefore, with this regulator it is impossible to reduce the voltage less than 110 volts. As practice shows, this is not necessary, since at a minimum voltage the tip temperature is so low that the tin barely melts.

The ratings of the parts presented in the diagram are selected for collaboration with high-power soldering irons. If you do not need it, then the power elements, thyristor and diode can be replaced with less powerful ones. If you don’t have a two-watt resistor R 5 with a nominal value of 30 kilo ohms, then it can be made up of two 15 kilo ohm resistors connected in series, like mine:

This device does not require any configuration. Assembled correctly and from serviceable parts, it starts working immediately.

Attention! Be careful. This temperature controller is not electrically isolated from the network. The secondary circuits have a high potential.

It remains to choose the appropriate size of the case. Place the socket for the soldering iron:

It is not necessary to bring the fuse out, for example, I have it soldered into the break in the power cord. But the variable resistor must be installed in a convenient place and, of course, the scale must be graduated, for example, in volts:

The resulting regulator is very reliable, which is time-tested, and it will serve you for many years, and the soldering iron will thank you.